The basic premise of the discussion was Hawking noting that, if most of the work of a future society was performed by machines, then how we occupied ourselves instead was much more of a social, political, economic, ethical, demographic, etc. question than it was technological. The rebuttal was essentially:

That’s silly: the old jobs will be replaced by new ones,

Please don’t say nasty things about capitalism,

Scientists should stick to science.

So how much of this criticism was justified and how much of it was simply The Establishment closing ranks?